Hermaphroditic spawning by the gonochoric pillar coral Dendrogyra cylindrus
Scleractinian corals typically reproduce sexually as either gonochoric (separate male and female) or hermaphroditic (producing both eggs and sperm) colonies. The Caribbean pillar coral Dendrogyra cylindrus has been classified as gonochoric, but multi-year spawning observations at a Florida Keys site revealed incidences of hermaphroditism. Separate clonal colonies (ramets) of a single genet released either male or female gametes. Furthermore, 22% of observed ramets produced both eggs and sperm within different regions of a single colony. Over multiple years, one ramet switched from female to hermaphrodite, one from male to hermaphrodite, and one from hermaphrodite to male. Proposed evolutionary mechanisms include size- or age-based energy allocation, environmental energy allocation, or chemically induced change in a single-sex region. Because of the low population density of D. cylindrus in the Florida Keys, sexual partners are scarce, and hermaphroditism may be a strategy to yield higher rates of successful sexual reproduction. The findings also have implications for future restoration efforts aiming to strategically outplant individuals to maximize in situ fertilization.
KeywordsDendrogyra cylindrus Pillar coral Spawning Hermaphrodite Gonochoric Sexual pattern
This research was enabled by NOAA Award NA 10NMF4720029, US Fish and Wildlife Service grants program (FA F13AF01085), and Florida’s Wildlife Legacy Initiative (State Wildlife Grants CFDA No. 15.634) to the Florida Fish and Wildlife Conservation Commission and a Florida Fish and Wildlife Conservation Commission subcontract (SW13059) to Pennsylvania State University. It was conducted under permit FKNMS-2013-085-A1 from the Florida Keys National Marine Sanctuary. We are grateful to staff and volunteers from the Florida Aquarium, Keys Marine Laboratory, Florida International University, Florida Fish and Wildlife Research Institute’s South Florida Research Lab, SUNY at Buffalo, and Dry Tortugas National Park for observations at other locations. Thanks also to two external reviewers for comments that improved this manuscript. Chan was supported by the National Science Foundation (NSF) Graduate Research Fellowship Program under Grant No. DGE1255832. The conclusions drawn in this work are those of the authors and do not necessarily reflect the views of the NSF.
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On behalf of all authors, the corresponding author states that there is no conflict of interest.
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